MACE Traumatic Brain Injury Pathophysiology

Question 1

What is a concussion (mild TBI)?

Accepted Answer

A traumatic brain injury caused by a bump, blow, jolt, or blast that alters brain function, typically without structural damage visible on standard imaging

Answer

Concussion is a functional (not structural) brain injury that disrupts normal neural function through metabolic cascade, ionic imbalance, and neuroinflammation, usually with normal CT and MRI findings.

Question 2

What is the neurometabolic cascade following concussion?

Accepted Answer

A series of cellular and metabolic changes including ionic flux, energy crisis, axonal injury, and neuroinflammation that impair brain function

Answer

After concussion, potassium floods out of cells while calcium rushes in, creating an energy crisis. Mitochondrial dysfunction, oxidative stress, and neuroinflammation follow, explaining symptoms even without visible structural damage.

Question 3

What is second impact syndrome?

Accepted Answer

A rare but potentially fatal condition where a second concussion occurs before the first has fully resolved, causing rapid brain swelling

Answer

Second impact syndrome occurs when the brain, still metabolically vulnerable from a prior concussion, sustains another impact. This can trigger catastrophic cerebral edema with potentially fatal brain herniation.

Question 4

How do blast injuries cause TBI in military settings?

Accepted Answer

Primary blast waves create rapid pressure changes that damage brain tissue, axons, and blood vessels even without direct head impact

Answer

Primary blast TBI results from the overpressure wave passing through the skull, causing tissue compression and expansion. Secondary (debris), tertiary (body displacement), and quaternary (heat, chemicals) mechanisms also contribute.

Question 5

What is post-concussion syndrome (PCS)?

Accepted Answer

A condition where concussion symptoms persist beyond the expected recovery period, typically longer than 3 months after injury

Answer

PCS involves persistent symptoms (headache, dizziness, cognitive difficulties, sleep disturbance, mood changes) beyond normal recovery timeframes. Risk factors include prior concussions, female sex, pre-existing mental health conditions, and delayed treatment.

MACE - Military Acute Concussion Evaluation Practice Test

MACE - Military Acute Concussion Evaluation Practice Test

MACE Traumatic Brain Injury Pathophysiology